Conventionally, in wireless communication systems such as, for example, wireless LAN systems, encrypted communication is performed in order to improve the security level. One of encryption systems used in this field is WEP (Wired Equivalent Privacy). This is a “common key encryption system”, by which the same encryption key (WEP key) is set in both the access point and the wireless LAN client. In this way, packets in communication are encrypted, and thus encrypted communication is performed. According to one method of WEP key generation, an authentication server which received a request for authentication from the wireless LAN client generates a WEP key. Then, the authentication server transmits the generated WEP key to the access point and the wireless LAN client (for example, Japanese Laid-Open Patent Publication No. 2004-15725). This allows the WEP key to be dynamically assigned and thus improves the security level.
However, the method disclosed in Japanese Laid-Open Patent Publication No. 2004-15725 has the following problem. Each time a request for authentication from the wireless LAN client is received, the authentication server generates and transmits a WEP key. When receiving authentication requests from a great number of wireless LAN clients at the same time, the authentication server needs to generate and transmit a great number of WEP keys at the same time. As a result, the processing load on the authentication server for establishing a communication connection is temporarily increased, which extends the processing time for the establishment.
Therefore, a feature of certain exemplary embodiments is to provide a communication system, a communication program, and a communication terminal capable of executing connection processing between an access point and the communication terminal easily and at a small processing load.
Certain exemplary embodiments have the following aspects to attain the feature mentioned above.
A first aspect of certain exemplary embodiments is directed to a communication system including an access point apparatus connectable to a network and a communication terminal wirelessly communicable to the access point apparatus. The access point apparatus comprises connection information storage means for storing connection information for generating key information for performing encrypted communication with the communication terminal and the key information generated from the connection information using a predetermined generation algorithm; and transmission means for transmitting the connection information. The communication terminal comprises receiving means for receiving the connection information; key information generation means for generating key information from the connection information using the same generation algorithm as used for generating the key information stored in the connection information storage means; and connection communication means for performing the encrypted communication with the access point apparatus using the key information generated by the key information generation means.
In a second aspect based on the first aspect, the connection information is character string data converted from related information including information on the access point apparatus using a predetermined conversion algorithm. The communication terminal further comprises recovery means for recovering the related information from the received connection information using the predetermined conversion algorithm; and the key information generation means generates the key information from the recovered related information.
In a third aspect based on the second aspect, the related information includes specific information which indicates that the access point apparatus is a communication target compatible with the communication terminal. The communication terminal further comprises specific information storage means for storing specific information; and determination means for determining whether or not the access point apparatus is a communication target, based on the specific information included in the related information and the specific information stored in the stored information storage means. The key information generation means generates the key information only when the determination means determines that the access point apparatus is a communication target.
In a fourth aspect based on the second aspect, the related information includes location information which indicates a location at which the access point apparatus is installed. The communication terminal further comprises communication game execution means for executing a predetermined communication game using the encrypted communication performed by the connection communication means; and content change means for changing a content of the communication game based on the location information included in the related information.
In a fifth aspect based on the second aspect, the related information includes information on the access point apparatus and random information formed of a predetermined numerical value or character string data. The key information generation means generates the key information based on the related information including the information on the access point apparatus and the random information.
A sixth aspect according to certain exemplary embodiments is directed to a communication terminal communicable with an access point apparatus having stored therein connection information, including generation information for generating key information for performing encrypted communication, and the key information generated from the connection information using a predetermined generation algorithm. The communication terminal comprises receiving means for receiving the connection information transmitted from the access point apparatus; key information generation means for generating key information from the received connection information using the predetermined algorithm; and connection communication means for performing the encrypted communication with the access point apparatus using the generated key information.
A seventh aspect of certain exemplary embodiments is directed to a storage medium having stored thereon a communication program to be executed by a communication terminal communicable with an access point apparatus, which has stored therein connection information, including generation information for generating key information for performing encrypted communication, and the key information generated from the connection information using a predetermined generation algorithm. The communication program comprises a receiving step of receiving the connection information transmitted from the access point apparatus; a key information generation step of generating key information from the received connection information using the predetermined generation algorithm; and a connection communication step of performing the encrypted communication with the access point apparatus using the generated key information.
According to the first aspect, key information can be generated by the communication terminal. Therefore, the processing load of key information generation is shared by a plurality of communication terminals and thus the load on each terminal is alleviated, as opposed to the case where the key information is generated by one server or the like. As a result, the time required for establishing the connection can be reduced. In addition, the encrypted communication can be performed without requiring the user of the communication terminal to do the settings for the encrypted communication. Since a specific type of communication terminals include key information generation means, illegal access from other types of communication terminals can be avoided.
According to the second aspect, the related information is first converted into predetermined character string data and then transmitted. The communication terminal recovers the related information and then generates the key information. Therefore, in order to perform the encrypted communication with the access point, the communication terminal needs to have means for generating the key information and also means for recovering the related information. Thus, a higher level of security is provided against illegal access from communication terminals other than the specific type of communication terminals.
According to the third aspect, erroneous connection with an access point apparatus which is not acceptable as a communication target, for example, an access point apparatus of another business entity, can be avoided.
According to the fourth aspect, the content of the communication game executed by the communication terminal can be varied for each access point apparatus connected to the communication terminal. Thus, the game can progress differently with different access point apparatuses, and the user is not bored with the game.
According to the fifth aspect, even if the access point apparatus changes the key information, the user does not need to do any corresponding setting on the communication terminal. This provides the user with an environment of easy encrypted communication. Since the key information can be changed by the access point apparatus without considering the situation of the communication terminal, the key information can be changed, for example, periodically and thus the security level can be improved.
A communication terminal and a communication program according to certain exemplary embodiments provide the same effects as those of the first aspect.
These and other features, aspects, and advantages of certain exemplary embodiments will become more apparent from the following detailed description of the exemplary embodiments when taken in conjunction with the accompanying drawings.